A double suction self-balancing dynamic seal molten urea pump and method of use thereof

Abstract

This invention relates to the field of urea pump technology and discloses a dual-suction self-balancing power-sealed molten urea pump and its usage method. The pump includes a base, a pump body, a first motor, and a feeding assembly. The feeding assembly is connected to the pump body. The feeding assembly includes a valve with a valve core rotatably mounted inside. A second motor is connected to the valve core. Two sets of transition pipes are connected to both sides of the valve, and a U-shaped pipe connects the two sets of transition pipes. A filter assembly is installed in each set of transition pipes, and a drive mechanism is provided in each set of transition pipes. Inspection ports are provided on the side walls of the transition pipes. This invention, by setting up a dual-channel switchable feeding channel, a negative pressure driven filter plate displacement mechanism, and an automatic channel sealing structure, allows for online removal, cleaning, and replacement of clogged filter plates while the pump is running normally. Simultaneously, it automatically seals non-working flow channels, preventing air from entering the pump cavity and affecting the negative pressure conveying state, improving the continuity of material conveying, and reducing the risk of production downtime.

Description

Technical Field

[0001] This invention belongs to the field of urea pump technology, specifically, it relates to a dual-suction self-balancing power-sealed molten urea pump and its usage method. Background Technology

[0002] Molten urea conveying is a key process in chemical production processes such as melamine and urea synthesis. Centrifugal pumps are typically used to transport urea in a high-temperature molten state. This type of operation requires the conveying equipment to have stable suction capacity, good sealing performance, and strong anti-crystallization and anti-clogging properties. Currently, most liquid urea pumps adopt a cantilever centrifugal structure, double impeller dynamic seal, and steam insulation structure, which can adapt to the high temperature and easy crystallization characteristics of molten urea to a certain extent. They are mainly used for continuous conveying of molten urea media containing a small amount of particles and easy crystallization, ensuring a stable material supply for chemical production lines.

[0003] However, existing molten urea transfer pumps use a single-channel feed, and the inlet filter is easily clogged by crystals or impurities in the medium. Once a blockage occurs, the machine must be stopped for disassembly and cleaning, which directly causes production line interruption and affects production efficiency.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows: A dual-suction self-balancing power-sealed molten urea pump includes a base, a pump body, a first motor, and a feeding assembly. The pump body and the first motor are mounted on the base, connected by a coupling. The pump body has an outlet and an inlet, and the inlet is connected to the feeding assembly. The feeding assembly includes a valve, two sets of transition pipes, a U-shaped pipe, and a main pipe. A valve core is rotatably installed inside the valve, and a second motor is connected to the valve core. Two sets of transition pipes are connected to both sides of the valve, and a U-shaped pipe connects the two sets of transition pipes. The main pipe is connected to the middle of the U-shaped pipe. Filter assemblies are installed in both sets of transition pipes. A drive mechanism for sealing the U-shaped pipe and moving the filter assemblies is provided in each set of transition pipes. Inspection ports are provided on the side walls of the transition pipes, and connection holes are provided in the U-shaped pipes. Sealing cores and compression springs are installed in the connection holes.

[0006] In a preferred embodiment of the present invention, the pump body is provided with a drive shaft, the first motor is provided with an output shaft, one end of the coupling is connected to the drive shaft and the other end is connected to the output shaft, and a sealing gasket is installed between the feed inlet of the pump body and the valve.

[0007] In a preferred embodiment of the present invention, the valve is provided with a feeding pipe, a first feeding pipe and a second feeding pipe, the valve core is provided with a central flow channel, and a rotating shaft is connected to the valve core, the rotating shaft being connected to the output end of a second motor.

[0008] In a preferred embodiment of the present invention, the driving mechanism includes a piston cylinder, a piston plate, a piston rod, a sealing pipe, and a filter plate. Both sets of transition pipes have piston cylinders coaxially fixed inside them. A piston plate is slidably installed inside the piston cylinder. A return spring is also installed inside the piston cylinder. One end of the return spring abuts against the piston plate, and the other end abuts against the piston cylinder. A piston rod is connected to the end face of the piston plate. The piston rod passes through the piston cylinder and extends to the outside of the piston cylinder. A filter assembly is connected to the end of the piston rod.

[0009] In a preferred embodiment of the present invention, the filter assembly includes a sealing tube and a filter plate. A plurality of connecting rods are evenly connected to the end of the piston rod. The end of the connecting rod is connected to the sealing tube. An installation groove and a pick-and-place groove are provided inside the sealing tube. The filter plate is detachably installed in the installation groove. A handle is connected to the filter plate. The handle is located in the pick-and-place groove.

[0010] In a preferred embodiment of the present invention, a through hole is provided at the end of the piston cylinder.

[0011] In a preferred embodiment of the present invention, the main pipe is vertically connected to the middle section of the U-shaped pipe, a flange is installed at the end of the main pipe, and the two ends of the U-shaped pipe are respectively sealed and connected to the side walls of two sets of transition pipes.

[0012] In a preferred embodiment of the present invention, a connecting pipe is provided between the U-shaped pipe and the two sets of transition pipes. One end of the connecting pipe is sealed and connected to the side wall of the U-shaped pipe, and the other end passes through the transition pipe and is connected to the side wall of the piston cylinder.

[0013] In a preferred embodiment of the present invention, a plurality of support columns are installed on the base, and pipe supports are connected to the plurality of support columns. The plurality of pipe supports are respectively supported on the outer walls of the U-shaped pipe and the main pipe, and an inspection cover is detachably installed on the inspection port.

[0014] The method of using the aforementioned dual-suction self-balancing dynamic seal molten urea pump comprises the following steps: S1: Before use, add mechanical oil to the bearing oil tank, check and adjust the tightness of the packing gland, and manually rotate the coupling to confirm that the rotation is even and there is no friction or jamming. S2: Before starting, open the cooling water pipeline and the steam insulation pipeline. The cooling water pipeline uses circulating cooling water to reduce the operating temperature of the bearing to prevent the bearing from overheating and being damaged. The steam insulation pipeline keeps the molten urea in a high-temperature molten state to prevent the medium from cooling and crystallizing in the pump and blocking the flow channel, thus ensuring smooth delivery. S3: Start the first motor and check that the motor current, pump vibration and noise are all normal; S4: The first motor drives the drive shaft to rotate through the output shaft and coupling, which causes the impeller inside the pump body to rotate and form a stable negative pressure conveying environment. Molten urea enters the U-shaped pipe through the main pipe. The impeller rotation creates negative pressure, which attracts the sealing core and compresses the compression spring. The sealing core leaves the connection hole, keeping the U-shaped pipe open. After diversion, it enters the transition pipe on one side, is filtered by the filter plate, and enters the first feed pipe of the valve. It enters the pump chamber through the central flow channel of the valve core, the feed pipe and the inlet, and is discharged under pressure from the outlet. S5: When the filter plate in the transition pipe on one side is blocked, the compression spring and the reverse suction force push the sealing core to block the connection hole, so that the negative pressure is concentrated on the corresponding connection pipe, and the second motor is started to drive the rotating shaft and valve core to rotate, so that the central flow channel is switched to connect with the second feeding pipe, and the feeding flow path is switched without interruption. S6: The negative pressure generated by the continuous operation of the pump body is transmitted to the piston cylinder on the blockage side through the connecting pipe, which drives the piston plate to slide against the elastic force of the return spring, and drives the piston rod, connecting rod, sealing pipe and filter plate to move towards the inspection port. The sealing pipe seals the connection between the U-shaped pipe and the corresponding transition pipe, and the filter plate moves to below the inspection port. S7: Open the inspection cover, hold the handle and remove the filter plate from the installation slot and the removal slot. After cleaning or replacing, reinstall it. S8: After switching, the flow path is normally fed. The negative pressure of the pump body, together with the reset spring, drives the other drive mechanism to reset, so that the sealing pipe and the filter plate return to the working position. Under the action of negative pressure, the sealing core opens the connection hole again, and the U-shaped pipe is restored to continuity. S9: When shutting down, stop the first motor. When the pump is to be out of service for a long period of time or on standby, close the inlet and outlet pipeline valves, drain the molten urea from the pump, rinse it clean, and store it properly.

[0015] Compared with the prior art, the present invention has the following advantages: This invention, by setting up a dual-channel switchable feeding channel, a negative pressure driven filter plate displacement mechanism, and an automatic channel sealing structure, can complete the online removal, cleaning, and replacement of clogged filter plates while the pump is running normally. At the same time, it can automatically seal non-working channels, prevent air from entering the pump cavity and affecting the negative pressure conveying state, improve the continuity of material conveying, the reliability of equipment operation, simplify maintenance operations, and reduce the risk of production downtime.

[0016] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0017] In the attached diagram: Figure 1 A three-dimensional diagram of a double-suction self-balancing dynamic seal molten urea pump; Figure 2 Rear view of a double-suction self-balancing dynamic seal molten urea pump; Figure 3 This is a schematic diagram of the assembly of the pump body and the first motor of a double-suction self-balancing dynamic seal molten urea pump. Figure 4 This is a schematic diagram of the installation of the feeding assembly of a double-suction self-balancing dynamic seal molten urea pump. Figure 5 A three-dimensional diagram of the feeding assembly of a double-suction self-balancing dynamic seal molten urea pump; Figure 6 This is a schematic diagram of the internal structure of the feeding assembly of a double-suction self-balancing dynamic seal molten urea pump. Figure 7 A cross-sectional view of the feeding assembly and filter assembly of a double-suction self-balancing dynamic seal molten urea pump; Figure 8 A cross-sectional view of the drive mechanism and filter assembly of a double-suction self-balancing dynamic seal molten urea pump; Figure 9 An exploded view of the drive mechanism and filter assembly of a dual-suction self-balancing dynamic seal molten urea pump.

[0018] In the diagram: 1. Base; 2. Pump body; 201. Drive shaft; 202. Discharge port; 203. Inlet port; 3. First motor; 301. Output shaft; 4. Coupling; 5. Valve; 501. Feeding pipe; 502. First feeding pipe; 503. Second feeding pipe; 6. Valve core; 61. Central flow channel; 7. Rotating shaft; 8. Second motor; 9. Transition pipe; 10. U-shaped pipe; 11. Main pipe; 12. 13. Connecting pipe; 14. Piston cylinder; 15. Piston plate; 16. Piston rod; 17. Connecting rod; 181. Sealing pipe; 182. Pick-up and drop-off slot; 19. Installation slot; 20. Filter plate; 21. Handle; 22. Pipe support; 23. Support column; 24. Inspection port; 25. Inspection cover; 26. Flange; 27. Sealing gasket; 28. Through hole; 29. ​​Connecting hole; 30. Sealing core; 31. Compression spring; 32. Return spring. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention.

[0020] like Figures 1 to 9 As shown, a double-suction self-balancing dynamic sealed molten urea pump and its usage method include a base 1, a pump body 2, a first motor 3, and a feeding assembly. The pump body 2 and the first motor 3 are mounted on the base 1, and a coupling 4 connects the pump body 2 and the first motor 3. The pump body 2 has a discharge port 202 and a feed port 203, and the feed port 203 of the pump body 2 is connected to the feeding assembly. The feeding assembly includes a valve 5, two sets of transition pipes 9, a U-shaped pipe 10, and a main pipe 11. A valve core 6 is rotatably installed inside the valve 5. A second motor 8 is connected to the core 6. Two sets of transition pipes 9 are connected to both sides of the valve 5, and a U-shaped pipe 10 is connected between the two sets of transition pipes 9. The main pipe 11 is connected to the middle of the U-shaped pipe 10. Filter components are installed in both sets of transition pipes 9. Drive mechanisms for sealing the U-shaped pipe 10 and moving the filter components are provided in both sets of transition pipes 9. Inspection ports 23 are opened on the side walls of the transition pipes 9, and connection holes 28 are opened in the U-shaped pipe 10. Sealing cores 29 and compression springs 30 are installed in the connection holes 28. In this configuration, the feeding component adopts a dual-channel independent structure, which can realize a non-stop operation mode of one channel for normal conveying and one channel for online maintenance. The sealing cores 29 and compression springs 30 can automatically seal the connection holes 28 when the filter plate 19 is blocked, so that the negative pressure is concentrated on the drive mechanism. This ensures that the drive mechanism can accurately drive the filter components to move and complete the channel sealing by using the negative pressure generated by the operation of the pump body 2. This prevents air from entering the pump chamber during maintenance and affecting the negative pressure conveying state, ensuring continuous and stable conveying.

[0021] like Figures 1 to 9 As shown in the specific embodiment, the pump body 2 is equipped with a drive shaft 201, the first motor 3 is equipped with an output shaft 301, one end of the coupling 4 is connected to the drive shaft 201, and the other end is connected to the output shaft 301. A sealing gasket 26 is installed between the feed inlet 203 of the pump body 2 and the valve 5. In this configuration, the first motor 3 transmits power through the coupling 4 to ensure stable operation of the impeller inside the pump body 2. The sealing gasket 26 improves the sealing performance at the connection between the feed inlet 203 and the valve 5, preventing external air from seeping in under negative pressure and avoiding problems such as pump cavitation, flow rate reduction, and abnormal vibration.

[0022] like Figures 1 to 9 As shown, valve 5 further includes a feeding pipe 501, a first feeding pipe 502, and a second feeding pipe 503. Valve core 6 has a central flow channel 61, and a rotating shaft 7 is connected to the valve core 6. The rotating shaft 7 is connected to the output end of the second motor 8. In this configuration, the second motor 8 can drive the valve core 6 to rotate, allowing the central flow channel 61 to quickly switch between the first feeding pipe 502 and the second feeding pipe 503, enabling the alternating use of the two feeding channels. The switching process is smooth and requires no machine downtime, meeting the requirements of continuous production.

[0023] like Figures 1 to 9 As shown, the drive mechanism further includes a piston cylinder 13, a piston plate 14, a piston rod 15, a sealing pipe 17, and a filter plate 19. Both sets of transition pipes 9 have piston cylinders 13 coaxially fixed inside them. A piston plate 14 is slidably installed inside the piston cylinder 13. A return spring 31 is also installed inside the piston cylinder 13, with one end abutting against the piston plate 14 and the other end abutting against the piston cylinder 13. A piston rod 15 is connected to the end face of the piston plate 14, passing through the piston cylinder 13 and extending to the outside of the piston cylinder 13. A filter assembly is connected to the end of the piston rod 15. In this configuration, the piston cylinder 13 and piston plate 14 cooperate to form a negative pressure drive structure, which can automatically operate under the negative pressure generated by the pump body 2. The return spring 31 can assist the piston plate 14 and the filter assembly in quickly resetting.

[0024] like Figures 1 to 9 As shown, the filter assembly further includes a sealing tube 17 and a filter plate 19. Several connecting rods 16 are evenly connected to the end of the piston rod 15, and the sealing tube 17 is connected to the end of each connecting rod 16. The sealing tube 17 has an installation groove 182 and a pick-and-place groove 181. The filter plate 19 is detachably installed in the installation groove 182, and a handle 20 is connected to the filter plate 19, located within the pick-and-place groove 181. In this configuration, the sealing tube 17 can automatically seal the connection between the U-shaped pipe 10 and the transition pipe 9 during relocation, preventing air intake during maintenance. The filter plate 19 can effectively intercept impurities and crystals in the medium, protecting the internal components of the pump body 2. The handle 20, in conjunction with the pick-and-place groove 181, facilitates quick installation and removal of the filter plate 19 by the operator.

[0025] like Figures 1 to 9 As shown, a through hole 27 is further provided at the end of the piston cylinder 13. In this configuration, the through hole 27, in conjunction with the return spring 31, enables the piston plate 14 and the filter assembly to be reset.

[0026] like Figures 1 to 9 As shown, the main pipe 11 is vertically connected to the middle section of the U-shaped pipe 10, and a flange 25 is installed at the end of the main pipe 11. The two ends of the U-shaped pipe 10 are respectively sealed and connected to the side walls of the two sets of transition pipes 9. In this configuration, the vertical arrangement of the main pipe 11 and the U-shaped pipe 10 makes the medium flow more uniform, the flange 25 facilitates quick sealing and connection with the external supply pipeline, and the U-shaped pipe 10 realizes the convergence and diversion of the two channels.

[0027] like Figures 1 to 9 As shown, furthermore, a connecting pipe 12 is provided between the U-shaped pipe 10 and the two sets of transition pipes 9. One end of the connecting pipe 12 is sealed and connected to the side wall of the U-shaped pipe 10, and the other end passes through the transition pipe 9 and connects to the side wall of the piston cylinder 13. In this configuration, the connecting pipe 12 is used to transmit the negative pressure in the U-shaped pipe 10 to the inside of the piston cylinder 13, ensuring that the drive mechanism can drive the filter assembly to move.

[0028] like Figures 1 to 9 As shown, furthermore, several support columns 22 are installed on the base 1, and pipe supports 21 are connected to each of the support columns 22. The pipe supports 21 support the outer walls of the U-shaped pipe 10 and the main pipe 11 respectively. An inspection cover 24 is detachably installed on the inspection port 23. In this configuration, the support columns 22 and pipe supports 21 provide support for the pipeline system, preventing the pipeline from shaking or deforming under negative pressure and medium flow. The inspection cover 24 can be quickly opened during maintenance, facilitating the removal and replacement of the filter plate 19.

[0029] This invention also discloses a method for using a dual-suction self-balancing dynamic seal molten urea pump, the steps of which are as follows: S1: Before use, add mechanical oil to the bearing oil tank, check and adjust the tightness of the packing gland, and manually rotate the coupling 4 to confirm that the rotation is even and there is no friction or jamming. S2: Before starting, open the cooling water pipeline and the steam insulation pipeline. The cooling water pipeline uses circulating cooling water to reduce the operating temperature of the bearing to prevent the bearing from overheating and being damaged. The steam insulation pipeline keeps the molten urea in a high-temperature molten state to prevent the medium from cooling and crystallizing in the pump and blocking the flow channel, thus ensuring smooth delivery. S3: Start the first motor 3 and check that the motor current, pump vibration and noise are all normal; S4: The first motor 3 drives the drive shaft 201 to rotate through the output shaft 301 and coupling 4, so that the impeller inside the pump body 2 rotates to form a stable negative pressure conveying environment. Molten urea enters the U-shaped pipe 10 through the main pipe 11. The impeller rotates to form a negative pressure, which attracts the sealing core 29 to compress the compression spring 30. The sealing core 29 leaves the connection hole 28, keeping the U-shaped pipe 10 open. After diversion, it enters the transition pipe 9 on one side. After being filtered by the filter plate 19, it enters the first feed pipe 502 of the valve 5. It enters the pump chamber through the central flow channel 61 of the valve core 6, the feed pipe 501 and the feed port 203, and is discharged under pressure from the discharge port 202. S5: When the filter plate 19 in the transition pipe 9 on one side is blocked, the compression spring 30 and the reverse suction force push the sealing core 29 to block the connection hole 28, so that the negative pressure is concentrated on the corresponding connection pipe 12, and the second motor 8 is started to drive the rotating shaft 7 and the valve core 6 to rotate, so that the central flow channel 61 is switched to connect with the second feeding pipe 503, and the feeding flow path is switched continuously. S6: The negative pressure generated by the continuous operation of the pump body 2 is transmitted to the blockage side piston cylinder 13 through the connecting pipe 12, which drives the piston plate 14 to slide against the elastic force of the return spring 31, and drives the piston rod 15, connecting rod 16, sealing pipe 17 and filter plate 19 to move towards the inspection port 23. The sealing pipe 17 seals the connection between the U-shaped pipe 10 and the corresponding transition pipe 9, and the filter plate 19 moves to below the inspection port 23. S7: Open the inspection cover 24, hold the handle 20 to remove the filter plate 19 from the mounting slot 182 and the pick-and-place slot 181, and reinstall it after cleaning or replacement. S8: After switching, the flow path is normally supplied. The negative pressure of the pump body 2, together with the reset spring 31, drives the other side drive mechanism to reset, so that the sealing pipe 17 and the filter plate 19 return to the working position. Under the action of negative pressure, the sealing core 29 opens the connection hole 28 again, and the U-shaped pipe 10 is restored to continuity. S9: When shutting down, stop the first motor 3. When the pump is not in use for a long time or is on standby, close the inlet and outlet pipeline valves, drain the molten urea in the pump, rinse it clean and store it properly.

[0030] The implementation principle of a dual-suction self-balancing dynamic seal molten urea pump and its usage method in this embodiment is as follows: The pump body 2 drives molten urea from the external pipeline through the flange 25 into the main pipeline 11, and then flows into the U-shaped pipeline 10 for diversion. After the medium enters the transition pipeline 9, it first passes through the filter plate 19 to filter impurities. The filter plate 19 can intercept particles and crystals, preventing impurities from entering the pump body 2 and causing wear on the impeller, drive shaft 201, and shaft seal components, thus ensuring stable operation of the pump unit. The filter plate 19 is installed in the mounting groove 182 inside the sealing pipe 17. The pick-and-place groove 181 opened in the sealing pipe 17 provides operating space for the handle 20. During normal operation, the inspection port 23 is closed by the inspection cover 24, keeping the interior of the transition pipeline 9 in a sealed state, preventing air infiltration during negative pressure transportation, and preventing pump body 2 from experiencing cavitation, vibration, flow rate reduction, and other malfunctions. The support column 22 and pipe support 21 provide stable support for the U-shaped pipe 10 and the main pipe 11, preventing the pipeline from shaking and deforming under the action of transportation and negative pressure, and ensuring smooth flow and structural stability.

[0031] Under normal operating conditions, the second motor 8 drives the rotating shaft 7 to keep the valve core 6 in position. The central flow channel 61 inside the valve core 6 connects the first feeding pipe 502 and the feeding pipe 501 to form the main feeding flow path. The negative pressure generated by the pump body 2 acts on the sealing core 29, overcoming the elastic force of the compression spring 30 and pulling the sealing core 29 away from the connecting hole 28, so that the U-shaped pipe 10 remains in a continuous state. The molten urea enters the first feeding pipe 502 after being filtered by the filter plate 19, and flows into the feeding pipe 501 through the central flow channel 61. It enters the pump chamber through the inlet 203 of the pump body 2, is pressurized under the action of the impeller rotation, and is finally discharged from the outlet 202 to the subsequent system. During this process, the transition pipe 9 corresponding to the second feeding pipe 503 and the filter assembly are in standby mode. The two flow channels are independent of each other and do not interfere with each other. The pump body 2 inlet is kept fully open. The flow rate is not adjusted by the inlet. The flow rate is controlled only by the outlet valve. The sealing gasket 26 between the feed inlet 203 and the valve 5 ensures a reliable seal at the docking position and prevents air from entering under negative pressure.

[0032] When the filter plate 19 corresponding to the first feed pipe 502 becomes blocked, the medium in that side channel cannot flow normally, and the negative pressure distribution in the U-shaped pipe 10 changes. The compression spring 30 pushes the sealing core 29 to block the connection hole 28, preventing the negative pressure in the U-shaped pipe 10 from passing through the connection hole 28. All the negative pressure is concentrated on the corresponding side connection pipe 12 and piston cylinder 13. At this time, the second motor 8 drives the rotating shaft 7 and valve core 6 to rotate, causing the central flow channel 61 to cut off the connection with the first feed pipe 502, while simultaneously forming a connection with the second feed pipe 503 and the feeding pipe 501, completing a seamless switch of the flow path. After the switch, the backup flow path immediately starts working. Molten urea enters the pump body 2 through another set of transition pipes 9 and filter plate 19, and the flow rate and pressure quickly return to stability, ensuring uninterrupted production.

[0033] As the flow path switching is completed, the negative pressure generated by the continuous operation of pump body 2 is transmitted to the piston cylinder 13 on the blocked side through connecting pipe 12. The negative pressure acts directly on piston plate 14, overcoming the elastic force of return spring 31 and pushing piston plate 14 to slide along the inner wall of piston cylinder 13. Piston plate 14 drives piston rod 15 to move synchronously. Piston rod 15 drives sealing pipe 17 and filter plate 19 to move as a whole towards inspection port 23 through connecting rod 16. During this process, sealing pipe 17 gradually closes the connection port between U-shaped pipe 10 and transition pipe 9, forming a seal to prevent external air from entering U-shaped pipe 10 after opening inspection cover 24, avoiding disruption of the negative pressure environment of pump body 2, and ensuring that the normal flow path delivery on the other side is not affected. When sealing pipe 17 is in place, filter plate 19 is just below inspection port 23. The operator can directly open inspection cover 24, hold handle 20 to pull filter plate 19 out of installation slot 182 and pick-up slot 181 for cleaning or replacement. After maintenance, filter plate 19 can be reinstalled.

[0034] Simultaneously, the negative pressure generated by pump body 2 acts on piston cylinder 13 on the normal operating side. Combined with the elastic force of return spring 31, this drives piston plate 14 and piston rod 15 to move in the opposite direction, resetting the sealing pipe 17 and filter plate 19 to their working positions and reopening the connection between U-shaped pipe 10 and transition pipe 9. Under the action of negative pressure, sealing core 29 overcomes the elastic force of compression spring 30 and leaves connection hole 28, restoring the open state of U-shaped pipe 10. The entire mechanism relies on the negative pressure of pump body 2 itself for drive, requiring no additional power. It completes online disassembly and assembly of filter plate 19, automatic channel sealing, negative pressure unblocking, and non-stop maintenance, improving equipment operational stability and continuity, reducing maintenance costs and production interruption risks. It is more suitable for the continuous, safe, and stable conveying of molten urea in melamine and urea projects.

[0035] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A double-suction self-balancing dynamic sealed molten urea pump, comprising a base (1), a pump body (2), a first motor (3), and a feeding assembly, characterized in that, A pump body (2) and a first motor (3) are mounted on the base (1). A coupling (4) is connected between the pump body (2) and the first motor (3). The pump body (2) has an outlet (202) and an inlet (203). A feeding assembly is connected to the inlet (203) of the pump body (2). The feeding assembly includes a valve (5), two sets of transition pipes (9), a U-shaped pipe (10), and a main pipe (11). A valve core (6) is rotatably installed inside the valve (5). A second motor (8) is connected to the valve core (6). The two sides of the valve (5) are respectively connected to... There are two sets of transition pipes (9), and a U-shaped pipe (10) is connected between the two sets of transition pipes (9). A main pipe (11) is connected in the middle of the U-shaped pipe (10). A filter assembly is installed in both sets of transition pipes (9). A drive mechanism for sealing the U-shaped pipe (10) and moving the filter assembly is provided in both sets of transition pipes (9). An inspection port (23) is opened on the side wall of the transition pipe (9). A connection hole (28) is opened in the U-shaped pipe (10). A sealing core (29) and a compression spring (30) are installed in the connection hole (28).

2. The double-suction self-balancing dynamic seal molten urea pump according to claim 1, characterized in that, The pump body (2) is provided with a drive shaft (201), the first motor (3) is provided with an output shaft (301), one end of the coupling (4) is connected to the drive shaft (201), and the other end is connected to the output shaft (301). A sealing gasket (26) is installed between the feed inlet (203) of the pump body (2) and the valve (5).

3. The double-suction self-balancing dynamic seal molten urea pump according to claim 1, characterized in that, The valve (5) is provided with a feeding pipe (501), a first feeding pipe (502) and a second feeding pipe (503). The valve core (6) is provided with a central flow channel (61). The valve core (6) is connected to a rotating shaft (7). The rotating shaft (7) is connected to the output end of the second motor (8).

4. The double-suction self-balancing dynamic seal molten urea pump according to claim 1, characterized in that, The drive mechanism includes a piston cylinder (13), a piston plate (14), a piston rod (15), a sealing pipe (17), and a filter plate (19). Both sets of transition pipes (9) have piston cylinders (13) coaxially fixed inside. The piston plate (14) is slidably installed inside the piston cylinder (13). A return spring (31) is also installed inside the piston cylinder (13). One end of the return spring (31) abuts against the piston plate (14), and the other end abuts against the piston cylinder (13). The piston rod (15) is connected to the end face of the piston plate (14). The piston rod (15) passes through the piston cylinder (13) and extends to the outside of the piston cylinder (13). The end of the piston rod (15) is connected to a filter assembly.

5. A double-suction self-balancing dynamic seal molten urea pump according to claim 1, characterized in that, The filter assembly includes a sealing tube (17) and a filter plate (19). Several connecting rods (16) are evenly connected to the end of the piston rod (15). The sealing tube (17) is connected to the end of the connecting rod (16). An installation groove (182) and a pick-and-place groove (181) are provided in the sealing tube (17). The filter plate (19) is detachably installed in the installation groove (182). A handle (20) is connected to the filter plate (19). The handle (20) is located in the pick-and-place groove (181).

6. A double-suction self-balancing dynamic seal molten urea pump according to claim 1, characterized in that, The piston cylinder (13) has a through hole (27) at its end.

7. A double-suction self-balancing dynamic seal molten urea pump according to claim 6, characterized in that, The main pipe (11) is vertically connected to the middle section of the U-shaped pipe (10). A flange (25) is installed at the end of the main pipe (11). The two ends of the U-shaped pipe (10) are respectively sealed and connected to the side walls of two sets of transition pipes (9).

8. A double-suction self-balancing dynamic seal molten urea pump according to claim 7, characterized in that, A connecting pipe (12) is provided between the U-shaped pipe (10) and the two sets of transition pipes (9). One end of the connecting pipe (12) is sealed and connected to the side wall of the U-shaped pipe (10), and the other end passes through the transition pipe (9) and is connected to the side wall of the piston cylinder (13).

9. A double-suction self-balancing dynamic seal molten urea pump according to claim 1, characterized in that, The base (1) is equipped with several support columns (22), and each of the support columns (22) is connected to a pipe support (21). The pipe supports (21) are respectively supported on the outer wall of the U-shaped pipe (10) and the main pipe (11). The inspection port (23) is detachably equipped with an inspection cover (24).

10. A method of using a double-suction self-balancing dynamic seal molten urea pump, characterized in that, The method of using the dual-suction self-balancing dynamic seal molten urea pump according to any one of claims 1-9 comprises the following steps: S1: Before use, add mechanical oil to the bearing oil tank, check and adjust the tightness of the packing gland, and manually rotate the coupling (4) to confirm that the rotation is even and there is no friction or jamming. S2: Before starting, open the cooling water pipeline and the steam insulation pipeline. The cooling water pipeline uses circulating cooling water to reduce the operating temperature of the bearing to prevent the bearing from overheating and being damaged. The steam insulation pipeline keeps the molten urea in a high-temperature molten state to prevent the medium from cooling and crystallizing in the pump and blocking the flow channel, thus ensuring smooth delivery. S3: Start the first motor (3) and check that the motor current, pump body vibration and noise are all normal; S4: The first motor (3) drives the drive shaft (201) to rotate through the output shaft (301) and coupling (4), so that the impeller inside the pump body (2) runs to form a stable negative pressure conveying environment. Molten urea enters the U-shaped pipe (10) through the main pipe (11). The impeller runs to form negative pressure, which attracts the sealing core (29) to compress the compression spring (30). The sealing core (29) leaves the connection hole (28), so that the U-shaped pipe (10) remains open. After diversion, it enters the transition pipe (9) on one side. After being filtered by the filter plate (19), it enters the first feed pipe (502) of the valve (5). It enters the pump chamber through the central flow channel (61) of the valve core (6), the feed pipe (501) and the feed port (203), and is discharged under pressure from the discharge port (202). S5: When the filter plate (19) in the transition pipe (9) on one side is blocked, the compression spring (30) and the reverse suction force push the sealing core (29) to block the connection hole (28), so that the negative pressure is concentrated on the corresponding connection pipe (12), and the second motor (8) is started to drive the rotating shaft (7) and the valve core (6) to rotate, so that the central flow channel (61) is switched to connect with the second feeding pipe (503), and the feeding flow path is switched continuously. S6: The negative pressure generated by the continuous operation of the pump body (2) is transmitted to the blockage side piston cylinder (13) through the connecting pipe (12), driving the piston plate (14) to slide against the elastic force of the return spring (31), and driving the piston rod (15), connecting rod (16), sealing pipe (17) and filter plate (19) to move towards the inspection port (23). The sealing pipe (17) seals the connection between the U-shaped pipe (10) and the corresponding transition pipe (9), and the filter plate (19) moves to below the inspection port (23). S7: Open the inspection cover (24), hold the handle (20) and remove the filter plate (19) from the installation slot (182) and the pick-and-place slot (181), and put it back after cleaning or replacement; S8: After switching, the flow path is normally supplied. The pump body (2) is under negative pressure and the reset spring (31) drives the other side drive mechanism to reset, so that the sealing pipe (17) and the filter plate (19) return to the working position. Under the action of negative pressure, the sealing core (29) opens the connection hole (28) again, and the U-shaped pipe (10) is restored to the open. S9: When shutting down, stop the first motor (3). When the pump is not in use for a long time or is on standby, close the inlet and outlet pipeline valves, drain the molten urea in the pump, rinse it clean and store it properly.

Images